JP2835750B2 - Method for producing carbon black - Google Patents

Description

The present invention relates to a method for producing carbon black having a wide aggregate distribution and a high primary structure.

[Conventional technology]

In recent years, there has been a strong demand for higher tire performance along with higher performance of automobiles. For this reason, in particular, there is an increasing demand for a reduction in heat build-up that promotes wear and rubber deterioration associated with high-speed running.

Generally, it is effective to mix carbon black having a small particle size as much as possible to impart abrasion resistance to the rubber component, but on the other hand, this type of carbon black reduces the heat build-up of the compounded rubber. It is known. For this reason, carbon black manufacturers have no choice but to develop carbon black that can combine these two properties simultaneously.

For these performance requirements, the distribution of the aggregate structure (Aggregate), which is the basic particle form of carbon black, is an important factor, and the mode diameter of the aggregate per the same specific surface area (st) and its distribution width (ΔDst) Is relatively effective.

On the other hand, one of the main characteristics of carbon black which has a remarkable effect for imparting reinforcing performance to the rubber component is a developed primary structure per the same specific surface area. This primary structure is based on compressed DBP oil absorption (AST
M 24M4DBP), which refers to a non-destructive aggregate structure.

Conventionally, various methods have been proposed for the production of carbon black for the purpose of increasing the control of the structure. For example, a method of dividing and introducing a feedstock into a furnace in two stages (US Pat. No. 3,445,190) Issue specification, 349
No. 0869) and a method in which a plurality of carbon black intermediate product gas streams generated in different systems are simultaneously introduced into the main reaction zone at a high speed so as to collide with each other in a straight-ahead state (Japanese Patent Publication No. 62-10581).

However, the above-mentioned manufacturing technique is relatively effective for improving the structure, but at the same time, causes an increase in the particle diameter and does not bring about a property modification mainly based on the aggregated structure.

(Problems to be Solved by the Invention) In order to increase the size of the agglomerated structure and widen the distribution thereof, it is necessary to create an atmosphere state that causes a non-uniform carbon black generation reaction in the reaction zone. Although the above-mentioned prior art method is one means for making the carbon black formation reaction non-uniform, it is insufficient in condition.

The present inventors have conducted various studies on the conditions for splitting and introducing the feedstock oil, which further makes the formation reaction of carbon black more heterogeneous, and as a result, the primary feedstock oil was identified at the stage of accelerating the combustion gas flow. The present invention has been demonstrated that it is extremely effective to simultaneously inject the secondary raw material oil from the peripheral edge of the gas flow at the same time as injecting the gas into the furnace axis direction at an angle.

Accordingly, an object of the present invention is to provide a method for producing carbon black having a wide aggregate distribution and an increased primary structure by selecting the above-described feedstock splitting and introducing conditions.

[Means for solving the problem]

In order to achieve the above object, a method for producing carbon black according to the present invention comprises the steps of: forming a combustion gas stream generated in a combustion zone into a tapered throat-like first reaction zone followed by a narrow-diameter second reaction zone; And the primary feed oil is injected in the first reaction zone in the direction of the furnace axis, and the secondary feed oil is injected from the outer periphery of the gas flow in a direction perpendicular to the furnace axis, so that the secondary feed oil is injected. A step of cooling a carbon black-containing gas stream in a rear wide-diameter reaction zone located downstream of a point where the feedstock is injected, and wherein the primary feedstock has a combustion rate (including fuel oil) of 95% or less. Injection is performed at an ejection angle θ of the following expression.

5 ° ≦ θ ≦ 2 tan ^-1 (P / 2l) where P is the inner diameter (mm) of the furnace at the point of injection of the secondary base oil, and l is the secondary from the injection point of the primary base oil. The distance (mm) to the injection point of the feedstock oil.

The apparatus for producing the carbon black of the present invention has a closed cylindrical furnace shape constructed of a refractory material and a steel outer shell, and has a tangential oxygen-containing gas supply duct at the furnace head and a furnace axial direction. A wide-diameter combustion zone with a combustion burner attached to the tub and an extendable primary feed oil injection nozzle,
A first reaction zone having a gently tapering throat shape connected to the first reaction zone, a second reaction zone having a narrow diameter, and a rear wide-diameter zone having an enlarged diameter in an opening shape. An oil furnace having a structure equipped with a plurality of secondary feed oil injection nozzles penetrating from the outer periphery in a direction perpendicular to the furnace is used.

The present invention uses a furnace having the above-described structure, and in the first reaction zone where the combustion gas flow generated in the combustion zone accelerates,
The primary feed oil is injected toward the furnace axis through the secondary feed oil injection nozzle, and at the same time, the secondary feed oil is injected into the first reaction zone through the secondary feed oil injection nozzle from the outer periphery of the gas flow. And cooling the gas stream containing carbon black in the downstream wide-diameter reaction zone by injecting at right angles to the furnace axis. At this time, the injection of the primary base oil and the injection of the secondary base oil may be performed on the same plane, but the injection point of the primary base oil is located downstream of the injection point of the secondary base oil. Is not preferred. The most preferable condition is that the secondary feedstock is injected into the narrowest portion of the first reaction zone, and the primary feedstock is injected upstream of the first reaction zone.

In the present invention, in the above embodiment, the primary feedstock is used in an amount such that the combustion rate including the fuel oil becomes 95% or less, and the ejection angle θ is set to [5 ° ≦ θ ≦ 2 tan ⁻¹ (P / 2l)]. (Where P is the inner diameter (mm) of the furnace at the point where the secondary feedstock is injected, and l is the distance (mm) from the location where the primary feedstock is injected to the location where the secondary feedstock is injected. It is an important requirement that the primary base oil be injected at an injection angle θ of less than 5 ° with a combustion rate exceeding 95% and the secondary base oil to be intermixed with the secondary base oil. The collision was incomplete and the desired nonuniformity of the carbon black formation reaction was not achieved, and 2 tan ^-1
Exceeding the value calculated from (P / 2l) causes inconvenient coke generation.

In addition, when an oxygen-containing gas is introduced into the downstream position adjacent to the injection point of the secondary feed oil, the non-uniformity of the carbon black generation reaction increases with the partial combustion of the feed oil, and the object of the present invention is further improved. The effect is promoted.

[Action]

According to the present invention, a predetermined ejection angle θ [5 ° ≦ θ ≦ 2 tan ⁻¹ (P / 2l)] directed toward the furnace axis at an amount of 95% or less of the combustion rate.
The primary feed oil injected in the above is introduced into the accelerated high-temperature combustion gas stream and enters a narrow-diameter reaction zone. In this process, the oil droplet fine particles of the primary feed oil follow extremely diverse thermal histories in terms of thermal and flow rates, and themselves also participate in various atmospheric formations, while being perpendicular to the furnace shaft from the outer periphery of the gas flow. The oil collides with the oil droplets of the second base oil injected in the direction at a stretch to cause an uneven carbon black generation reaction.

Such a series of processes effectively acts to form an increased aggregate distribution width and a primary structure in the produced carbon black.

〔Example〕

 Hereinafter, examples of the present invention will be described in comparison with comparative examples.

Examples 1 to 6 and Comparative Examples 1 to 2 A combustion zone (500 mm in diameter, diameter: 500 mm, in which a tangential air supply duct, a combustion burner in the furnace axis direction, and an extendable primary feed oil injection nozzle were coaxially mounted on the furnace head. 800mm), a throat-like first reaction zone (250mm in diameter at inlet, 180mm in diameter at outlet, 1000mm in length)
180mm diameter section length 300mm), subsequent second reaction zone (diameter 200mm, length 1000mm), rear large-diameter reaction chamber (diameter 500mm, length 6000mm) with opening and connected with quench for quenching
In the oil furnace furnace, six secondary feed oil injection nozzles penetrating in a direction perpendicular to the furnace axis from the furnace peripheral position corresponding to the narrowest diameter portion of the first reaction zone were inserted at equal intervals.

Using the manufacturing apparatus having the above structure, carbon black was manufactured using hydrocarbon fuel oil and raw material oil having the characteristics shown in Table 1 and changing the manufacturing conditions. Of these, two cases were performed under the condition that oxygen gas was blown through three nozzles from a position 200 mm downstream from the injection position of the secondary base oil (Examples 3 and 6). Further, for comparison, an example in which the feedstock was injected only in a direction perpendicular to the furnace axis (Comparative Example 1) and an example in which the combustion rate of the first feedstock deviated from the requirements of the present invention (Comparative Example 2) Are also shown in Table 2.

Table 2 shows the properties of the obtained carbon blacks in comparison with the application conditions.

From the results shown in Table 2, the examples satisfying the requirements of the present invention have significantly increased both the mode system (st) and the distribution width (ΔDst) of the aggregate while having the same specific surface area as compared with Comparative Example 1. And the 24M4DBP oil absorption also remains at a high level. In particular, in Examples 3 and 6 in which oxygen gas was blown immediately after the injection of the secondary stock oil, it was recognized that the effect became clear. In Comparative Example 2, almost no improvement effect was observed.

[Effects of the Invention] As described above, according to the method for producing carbon black according to the present invention, carbon black having a wide aggregate distribution and a high degree of primary structure can be efficiently produced.

Therefore, the compounded rubber can have both high abrasion resistance and low heat generation at the same time, so that it is extremely useful as carbon black for high-grade tire treads.

Claims (2)

(57) [Claims] 1. A combustion gas stream generated in a combustion zone is introduced into a first reaction zone having a tapered throat shape and a second reaction zone having a narrow diameter following the first reaction zone. The primary feed oil is injected toward the furnace, the secondary feed oil is injected at right angles to the furnace axis from the outer periphery of the gas flow, and the rear portion located downstream of the injection location of the secondary feed oil A step of cooling the carbon black-containing gas stream in a wide-diameter reaction zone, and injecting the primary feed oil at a firing rate (including fuel oil) of 95% or less at an injection angle θ of the following formula. Characteristic method for producing carbon black. 5 ° ≦ θ ≦ 2 tan ^-1 (P / 2l) where P is the inner diameter (mm) of the furnace at the point of injection of the secondary base oil, and l is the secondary from the injection point of the primary base oil. The distance (mm) to the injection point of the feedstock oil. 2. The method for producing carbon black according to claim 1, wherein an oxygen-containing gas is introduced into a downstream position adjacent to the injection point of the secondary feedstock.